An essential part of every building structure is an enclosing top surface, or roof. The basic function of all roofs is to provide a closing or sealing surface which prevents entry of wind, rain, snow, and cold into the building. Traditionally, roofs have been made of varied materials with correspondingly differing effectiveness. For sloped roofs, various types of overlaping shingles are generally employed with the down-slope overlap portion exceeding in width the exposed portion with vertical joints between shingle disposed above a monpenetrable shingle surface. Unfortunately, this requirement generally dictates the relatively thin thickness, and to some extent, the size and shape of the shingles and discourages the use of structurally strong construction arrangements. For example in the U.S. Pat. No. 2,264,546, to Oches, issued Dec. 2, 1941, a surface covering structure is disclosed which comprises a base member and a covering member each of which may be of diverse materials. However, the overlapping areas are small and consequently special provision, such as a backing strip, must be made to seal between adjacent members at the same level. In the Goss et al. patent, U.S. Pat. No. 2,297,353, issued Sept. 29, 1942, beveled siding is manufactured from scraps of material which are ordinarily wasted, but are effectively and securely united by a special tongue and groove arrangement whereby they compare favorably with long length lumber. In U.S. Pat. No. 2,519,950, issued Aug. 22, 1950, to Abraham there is disclosed an insulated clapboard siding comprising fiber board faced with mineral granules applied thereto. U.S. Pat. No. 2,624,920, issued Jan. 13, 1953, to Anderson relates to wooden shingles which are secured to a wooden backing and have interlocking tongue and groove connections. Two layers are employed, one layer being staggered relative to the other.
In a sloped roof, the connection of adjacent members becomes more critical due to the increasingly direct exposure to the effects of rain and snow with the consequent problems increasing as the slope decreases. Thus, despite structural advantages possible, it is seldom that vertical surface coverings as exemplified in the Oches patent are utilized for a sloping roof.